Manually operated riveting device



Jan. 27, 1970 HANS-GEORG BIER'MANN 3,491,578

MANUALLY OPERATED RIVETING' DEVICE Fiied'sepi. a. 1965 v INVENTOR HANS-GEORG BIERMANN ATTORNEY.

AUnited States Patent O U.S. Cl. 72-391 7 Claims ABSTRACT OF THE DISCLOSURE A manually operated riveting device for riveting of blind rivets consisting of a hollow rivet and a rivet shank to be broken olf, the device comprising a housing, two tong arms secured to the housing, one of the tong arms being secured immovably to the housing, and another of the tong arms being swingably mounted in the housing at one end thereof for manual operation. A chuck mechanism is provided and adapted to grip a shank of the rivet and a force transmission means comprising a single toothed gear arrangement between the swingably mounted tong arm and the chuck mechanism is provided in actuating the tool.

The present invention relates to a manually operated riveting device for riveting of blind rivets consisting of a hollow rivet and breakable shank, comprising a housing, two tong arms, as well as a chuck mechanism for gripping the rivet shank for the purpose of riveting the blind rivet.

Devices for riveting of blind rivets are generally known, whereby the force required for the forming of the blind rivet is brought about manually. 'Ihese devices comprise substantially a tong-housing, which is designed on one side simultaneously to a tong arm and a movable tong arm, which is rotatably mounted in the housing. The chuck mechanism is pivoted to the movalble tong arm. By operation of the movable tong arm, the riveting operation is performed. The necessary force is, thereby, kept within permissible limits such, that the movable leg member is formed as a lever arm, whereby the length of the lever arm, gripped by the hand of an operator, is appreciably larger than the lever arm to which the chuck mechanism is pivoted. The movable tong arm is formed as a two-armed lever such, that the force required for the riveting can be obtained by manual operation.

- These known riveting devices, which are known as riveting tongs, are limited in their application to the riveting of blind rivets. Only rivets having smaller diameters can be riveted with such riveting tongs. In case of large diameters of the rivets, it is no more possible,

due to the required transmission or force, to realize a device for manual operation. These known manually operated riveting devices can be used, therefore, only within a limited range for the riveting of blind rivets.

A manually operated device for the working of larger blind rivets has also been known, however, which operates in accordance with the principle of the Nuernberg scissorgrid. This device is capable of providing the force required for the transmission for the working of larger rivet structures, has, however, the drawbacks, that, on the one hand, it is in the extended position very long and not handy, and on the other hand, very dangerous for the operator due to the scissor-grid. For instance, it is possible that the operator is clamped in at the pivoting points of the scissor-grid. A further drawback of this device resides in the fact, that during riveting the pressure force to be exerted and applied manually is transferred upon the riveting point and thereby surface damages can occur on the working pieces. In addition, the required force for the Working of larger blind rivets is still appreciably great.

Patented Jan. 27, 1970 It is, therefore, one object of the present invention to provide a manually operated riveting device, which serves in particular for the riveting of larger blind rivet diameters and, in spite of the requirement of relatively large force, is easily and safely operated by hand.

It is another object of the present invention to provide an arrangement for a force transmission, which comprises a rotatably mounted toothed gear element, which,.on the one hand, meshes with a pinion provided on one operated tong arm, and on the other hand, with a gear rack, which is connected with the chuck mechanism. Due to the arrangement for the transmission of forces, in accordance with the present invention, advantageously larger blind rivets, related to the diameter of the shaft and of the rivet shank, can be easily riveted by hand. The operation takes place, thereby, by movement of the pivoted tong arm, without exposing, there-by, any pivoting points, which would permit a clamping, squeezing or the like of the hands of the operator. Furthermore, no pressure is exerted to the riveting point or the surface of the work piece. The arrangement of transmission, in accordance with the force required for the riveting is elective exclusively as return force.

Itis still another object of the present invention to provide a manually operated riveting device, wherein in order to bring about a favorable'transmission ratio between the force to be exerted by hand and the force required for the riveting, it is suitable, if one end of the toothed gear element formed as a segment has a diiferent module than the other end.

In order to favor further the transmission ratio of the moving parts, the toothed gear element is advantageously mounted like a lever.

For instance, the toothed gear element can comprise one part, which amounts to a simple structure, or it can form a segment of a large toothed gear and of a small toothed gear, whereby both parts are soldered, welded or the like. The latter has the advantage that the manufacturing costs are lower than those for the production of one complete part.

A further advantage is added thereto such, that the gear rack has an inner bore, which makes it possible, that the broken-off rivet shank can also fall out rearwardly. If, for instance, riveting has to be done at points, at which the manually operated riveting device is set up upwardly, then it is no more necessary to lower it after a riveting process has been performed, in order to have the broken-off riveting shank fall out forwardly, rather the latter can fall out freely rearwardly.

In a manually operated riveting device it is further of importance, that it is, as much as possible, of a light weight. For this reason it is of advantage to recess the toothed gear element, so that its weight is appreciably reduced.

A further reduction of weight can be obtained such, that the bearing points for the tong arm to be operated and for the toothed gear element are formed as eyes and do not amount to a complete housing.

In order to bring about an absolutely free fall of the broken-off riveting shank rearwardly through the gear rack, it is suitable, if the bearing point for the gear rack l extends as a bore through the entire housing. By such present invention will be clearly understood in connection with the accompanying drawing, in which:

FIG. l is an axial section of a manually operated riveting device, designed in accordance with the present invention;

FIG. 2 is a section along the lines 2-2 of FIG. 1; and

FIG. 3 is an axial section of a blind rivet obtained by the device designed in accordance with the present invention.

Referring now to the drawing, and in particular to the embodiment of the riveting device disclosed in FIG. 1, the riveting device comprises a tong housing 1 having a U- shaped cross-section and having an inner tubular bore portion 2 extending therethough at the apex 1a of the housing. Two bearing eyes 3 and 4 are provided on the tong housing 1, each of the bearing eyes 3 and 4 constituting a pivot point. An immovable tong arm 5 is mounted in the apex 1a of the housing 1 at its base 1b, preferably by means of a blind rivet 6. For the proper operation ofthe device, this tong arm 5 has a handle 7, for instance, of plastic material.

A second tong arm 8 is rotatably mounted in the bearing eye 4 adjacent the open end 1c (the upper end in the drawing) of the U-shaped housing. This second tong arm 8 has likewise at its free end a handle 9. The other end of the tong arm 8 is rigidly connected with a pinion 10 of a predetermined module.

A toothed gear element 11 is rotatably mounted in the second bearing eye 3. The toothed gear element 11 comprises a segment, one end of which has a gear ring part 12 of a module, which corresponds with the module of the pinion 10. The other end of the toothed gear element 11 is formed as a part pinion 13 of a different module than that of the other gears. As can be easily determined, the toothed lgear element 11 has, in the embodiment shown in the drawing, a lever-like mounting, whereby a favorable transmission ratio is obtained. Practically, it is also possible that the mounting of this part is performed at a different point in the manner of a three-armed lever.

A gear rack 14 substantially circular in cross-section is slidably mounted in the inner bore 2 of the housing 1. The tubular bore portion 2 has a longitudinal slot 2a between the apex 1a and the upper open end 1c. The teeth of this gear rack 14 are formed facing the longitudinal slot 2a and correspond as to their module to the module of the part pinion 13 of the toothed gear element 11. Both parts engage each other through the slot 2a. The gear rod 14 carries the so-called chuck mechanism, which comprises in known manner chuck cheeks 15, a pressure bushing 16 and a spring 17 effective on both mentioned parts. The lastnamed elements are disposed in a chuck housing 18 which is equipped with an intermediate chuck member 19. The intermediate member 19 is locked by means of a counter nut 20 in its position on the gear rack 14 and is threadedly connected with the chuck housing 18.

The chuck mechanism is surrounded by a sleeve 21, which is screwed into the tong'housing 1. The free end of the sleeve 21 has a so-called mouth-piece 22 for receiving the blind rivet. The inner end of the mouth-piece 22 is designed such, that the chuck cheeks 15 engaging the mouthpiece 22 are opened in their inoperative position.

The device designed in accordance with the present invention operates in the following manner:

The movable tong arm 8 can be moved in either direction of the arrow 23. The operative position of the movable tong arm 8 is Shown in dotted lines. In order to insert and to rivet the blind rivet 24 comprising a hollow rivet 25, and a rivet shank 26, which can lbe broken off, the manually operated riveting device must be brought into its inoperative position, as shown in the drawing. In this position, the chuck cheeks 15 are pressed towards the rear side of the mouth-piece 22 and are, thereby, opened in a counter-effect to the spring 17. In this position the blind rivet 24 can be inserted into the mouth-piece 22 and thus into the chuck mechanism.

The riveting takes placein such manner, that the tong arm 8 is turned into its operative position in the direction of the arrow 23, to assume the position shown in dotted lines. By this movement, the rotary movement of the tong arm 8 is transmitted to the toothed gear segment 11 which rotates simultaneously, however, in opposite direction. The part pinion 13 performs, thereby, a counter-clockwise rotation in the direction of the arrow 27. This rotation is transmitted to the gear rack 14 and in particular as a translation movement. The gear rack 14 moves, thereby, in the direction of the arrow 28 and pulls, thereby, the

chuck mechanism in the same direction. Due to the return movement of the chuck mechanism, due to the conical arrangement of the chuck cheeks 15, the rivet shank 26 of the blind rivet 24 is gripped by means of the spring 17 and pulled in the same direction.

Upon termination of the riveting process, that means, when the head 29, as shown in FIG. 3, has been formed, the rivet shank 26 tears off at a predetermined point, the so-called breaking point 30. The device is mounted such, that a suicient working stroke is provided, in order to terminate the riveting process in one working step in connection with a predetermined thickness of the material.

Upon obtaining the end position of the moved tong arm 8, the latter is returned into its original opening position, whereby the chuck cheeks 15 open again and the broken-olf rivet shank 26 falls out either forwardly through the mouth-piece 22 or rearwardly through the inner bore 31 in the gear rack 14, depending upon the position and mounting of the manually operated riveting device.

The modules and the bearing arrangement of the moved parts of the force transmission arrangement, in accordance with the present invention, are chosen such, that maximal pulling forces are produced in the chuck mechanism with a small manual force requirement.

The present invention is not limited to the embodiment shown in the drawing. For instance, the bearing points can be arranged differently than shown and the transmission path can be varied and formed differently, respectively. Essential is, however, the transmission ratio obtained by the present invention.

While I have disclosed one embodiment of the present invention, it is to be understood that this embodiment is given by example only and not in a limiting sense, the scope of the present invention being determined by the objects and the claims.

I claim:

1. A manually operated riveting device for riveting of blind rivets consisting of a hollow rivet and a rivet shank to be broken olf, said device comprising a housing substantially U-shaped in cross-section and having a tubular bore portion at the apex thereof,

said tubular bore portion formed with a longitudinal slot between the apex and the opposite open end of its U-shape, the apex of the U-shape constituting the base portion of said tubular bore portion,

two tong arms secured to said housing,

one of said tong arms `being secured immovably to said housing adjacent said base portion,

another of said tong arms being swingably mounted in said housing at one end adjacent said open end of said U-shape,

a hollow sleeve screwed axially onto said tubular bore portion,

a chuck mechanism adapted to grip a shank of the rivet and operatively mounted in said hollow sleeve,

force transmission means comprising exclusively, a single toothed gear element rotatably mounted centrally within said U-shaped housing,

arcuate cut away eye formations on said housing constituting bearing means for said one end of said another of said tong arms and for said toothed gear element, respectively,

a pinion provided on said one said tong arms,

a gear rack substantially circular in cross-section and having an axial bore therethrough and slidably mounted in said tubular bore portion of said housing and having rack teeth facing said longitudinal slot,

Yend of said another of said toothed gear element having gear teeth being in mesh with said pinion on the one hand and with said rack teeth of said gear rack through said longitudinal slot on the other hand, and

means connecting said gear rack with said chuck mechamsm.

2. The device, as set forth in claim 1, wherein said toothed gear element comprises a segment having said gear teeth at opposite ends, and

the gear teeth disposed at one end have a module different from that of the other end.

3. The device, as set forth in claim 1, wherein said toothed gear element is lever-like mounted in said housing.

4. The device, as set forth in claim 1, wherein said toothed gear element is an integral member.

5. The device, as set forth in claim 1, wherein said toothed gear element comprises a segment of a larger gear and a segment of a smaller gear, and

plate means connecting said two segments.

6. The device, as set forth in claim 1, wherein References Cited UNITED STATES PATENTS 2,283,665 5/ 1942 Cadden 72-449 2,370,840 3 1945 Carlson 72-449 2,384,690 9/ 1945 Mullgardt 72-391 2,406,949 9/ 1946 Huck 72-391 CHARLES W. LANHAM, Primary Examiner GENE P. CROSBY, Assistant Examiner U.S. Cl. X.R. 

